Roller bearings typically provide an inner ring, an outer ring and at least two rows of rolling elements, such as rollers, arranged between the rings. Roller bearings of large diameter are generally loaded both radially and axially with relatively large loads. In this case, reference is made to an orientation roller bearing or slewing roller bearing.
Patent application FR-A1-2 694 610 describes a slewing roller bearing providing three row of rollers arranged between the inner and outer rings, and wherein two rows make it possible to withstand axial forces. The third row of rollers makes it possible to withstand radial forces, and is arranged between the cylindrical outer surface of the inner ring, and a groove formed in the bore in the outer ring. Slewing roller bearing are used in aggressive environments and further provides sealing elements to prevent exterior elements, such as dust, metal particles or water, from getting inside the bearing and damaging its components. A first sealing element is fixed to the inner ring and provides a sealing lip in sliding contact with the outer ring. A second sealing element is fixed to the outer ring and provides a sealing lip in sliding contact with the inner ring.
However, such sealing elements with only one lip are not sufficient to prevent the entry of water under high pressure flow, particularly during the bearing cleaning.
To further improve this seal-tightness and increase the life of the annular seal, it has already been proposed to provide an annular protective cover on top of the seal, generally of L-shaped section, the radial branch of which has an inner portion inserted into a peripheral groove of the inner ring of the bearing. This cover is fixed using pins which are inserted into inclined holes formed in the inner ring of the bearing, from points outside the cover, and which pass through this inner portion.
However, this arrangement is axially bulky and is complicated to implement. Furthermore, it presents a difficulty associated with the accessibility of the pins in view of the surrounding parts of the machine, if it presents a need to dismantle the cover for a cleaning or seal change service, for example, or to reassemble the cover.
It is therefore desirable that a slewing roller bearing provides effective sealing elements that prevent the entry of exterior element, particularly in aggressive environment, and easy to implement.